Search PubMed⌕ Search

Biomedical subjects

S Lewis

Publications and source records attributed to S Lewis.

At least 325 records · Page 18Linked to original sources
PubMed1991

Kallikrein does not modify the transepithelial potential of rat renal distal convoluted tubules.

The addition of kallikrein to the luminal solution of rabbit urinary bladder has been demonstrated to degrade amiloride-sensitive sodium channels in a time- and concentration-dependent manner. The aim of this study was to determine whether kallikrein has a similar effect on the amiloride-sensitive sodium channels present in the luminal membrane of the perfused rat distal convoluted tubule in vivo. The transepithelial potential (measured using conventional microelectrodes) was -11.9 +/- 2.2 mV [n = 10] and decreased to +0.4 +/- 0.7 mV [n = 10] in the presence of 5 mumol/l luminal amiloride. A 17-min perfusion of the tubular lumen with 100 units/l of porcine glandular kallikrein did not significantly alter the control transepithelial potential nor the change in potential elicited by amiloride. Similarly, the transepithelial potential was not altered by the perfusion of 100 nmol/l bradykinin.

Amiloride↗
PubMed1991

Pre-morbid adjustment and personality in psychosis. Effects of sex and diagnosis.

Pre-morbid schizoid and schizotypal traits and social adjustment were assessed blind to diagnosis by interviewing the mothers of 73 consecutively admitted patients with DSM-III schizophrenia or affective psychosis. Analysis of factors associated with pre-morbid deficits showed a highly significant interaction of diagnosis with sex, such that schizophrenic men showed much greater pre-morbid impairment than either schizophrenic women or men with affective disorder. Poor pre-morbid adjustment predicted an early age at first admission. The results can be explained by a neurodevelopmental disorder in some schizophrenic males.

Adolescent↗
PubMed1991

An esthetic titanium abutment: report of a technique.

New esthetic two-piece titanium abutment cylinders have recently been introduced for the Brånemark implant system. The conical design allows for the fabrication of fixed partial dentures with improved esthetics compared to the conventional abutment design. The improved feature provides for the ability to begin the restoration closer to the implant while still maintaining a titanium/soft-tissue interface. Two designs, one short and one long, are currently being produced. The components, techniques, and clinical advantages of the short two-piece esthetic abutment are reviewed.

Dental Abutments↗
PubMed1991

Host defense mechanisms in the peritoneal cavity of continuous ambulatory peritoneal dialysis patients. 2. Humoral defenses.

This is the second of a 2-part series reviewing host defense mechanisms of the peritoneal cavity of continuous ambulatory peritoneal dialysis (CAPD) patients. This article discusses humoral aspects of host defenses and accompanies the first article that focused upon cellular defenses. The purpose of this review is to provide a critical analysis of studies that have investigated the importance of peritoneal humoral immunity of CAPD patients in the pathogenesis of peritonitis. Specific attention is given to how CAPD alters normal humoral defenses of the peritoneal cavity and the clinical significance of such alterations.

Antibody Formation↗
PubMed1991

Host defense mechanisms in the peritoneal cavity of continuous ambulatory peritoneal dialysis patients. 1.

This article provides a review of studies on peritoneal white blood cells (WBC) in CAPD patients. To some extent these studies support the concept that the peritoneal cavity of these patients contains adequate-functioning WBC that can provide effective antimicrobial defenses when they are studied in dialysate-free media. Commercially available dialysis solutions significantly impair WBC function. In some patients with high incidences of peritonitis, there appears to be reduced bactericidal capacity of their peritoneal macrophages. CAPD seems to contribute to a state of both macrophage and lymphocyte activation in the peritoneal cavity. The clinical consequences of this chronic activation are not known.

Cytokines↗
PubMed1990

A comparison of blood gases and acid-base measurements in arterial, arterialized venous, and venous blood during short-term maximal exercise.

The purpose of this study was to determine the relationship between blood gases and acid-base measurements in arterial, arterialized venous, and venous blood measured simultaneously during short-term maximal exercise. Ten well-trained male cyclists performed a graded maximal exercise test on a cycle ergometer to determine the power output corresponding to their peak oxygen consumption (test I), and a short-term maximal test on a cycle ergometer at peak power output (test II). During test II arterial, arterialized venous and venous blood were sampled simultaneously for determination of partial pressures of oxygen and carbon dioxide, pH, bicarbonate (HCO3-), base excess (BE), and lactate (La). Samples were taken at rest, the end of 1 min of exercise (1 ME), at the end of exercise (EE), and at 2 min of recovery (REC). During test II, subjects maintained a peak power output of 370.6 (62.1) W [mean (SD)] for 4.5, SD 1.6 min. Except at rest venous and arterialized venous measurements tended to be the same at all sampling intervals, but differed significantly from measurements in arterial blood (P less than 0.05). BE was the only variable that rendered consistently significant correlations between arterial and arterialized venous blood at each sampling interval. The pooled correlation coefficient between arterial and arterialized venous BE was r = 0.83 [regression equation: BEa = (0.84 BEav)-0.51]. Arterial La was significantly higher than venous La at 1 ME (2.8, 0.7 vs 0.8, 0.3 mmol.l-1) and higher than both venous and arterialized venous La at EE.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Allergy to human seminal fluid: characterization of the allergen and experience with immunotherapy.

A 20-year-old woman was observed with a history of a severe generalized systemic reaction after topical contact with seminal fluid. A prick test with undiluted seminal fluid produced a 5.0 mm wheal-and-flare response with pseudopods. Prick tests with saliva and serum from the same source as the seminal fluid were negative. Measurement of IgE antibody to seminal-fluid allergen with a Biotin-Avidin ELISA technique yielded strong activity. No IgG antibody could be detected. Significant prick test reactivity could be found in Sephadex G-100 fractions that had a molecular weight range of 12,000 to 75,000 daltons and that contained approximately 5% of the total protein in the starting material. Isoelectric focusing fractions with strong skin test reactivity had a pI range of 5.4 to 6.6. These fractions contained one major protein band. Immunotherapy was conducted with a Sephadex fraction of seminal fluid during a 24-month period. A cumulative dose of 32 mg of protein was administered. No side effects other than local swelling occurred. Ten months after the start of immunotherapy, IgE antibody became unmeasureable, an effect that was demonstrated not due to the inhibitory effect of IgG antibody. IgG antibody rose progressively in this period. Clinically, the patient became less sensitive to topical contact. Although the natural history of seminal-fluid allergy is not known, immunotherapy may be effective.

Acute Disease↗
PubMed1990

A standardized assessment of patients referred to primary care and hospital psychiatric clinics.

General practice based psychiatric clinics have increased in number in recent years. Case-note and case-register data examining the nature of the psychiatric disorder of the patients seen in this setting have shown contradictory findings. In this study comparison of 113 patients referred to primary care and hospital out-patient clinics is made using standardized clinical and social measures. Our results show that both groups had similar degrees of physical and social dysfunction and comparable levels of psychiatric morbidity. However, in the primary care population there were more women, and schizophreniform psychoses predominated. In the hospital sample affective illnesses and personality disorders were more common. The majority of patients preferred to consult in the primary care setting.

Adolescent↗
PubMed1990

The relationship between regional variations in blood flow and histology in a transplanted rat fibrosarcoma.

The regional distribution of blood flow to the LBDS1 fibrosarcoma, transplanted into the subcutaneous site in rats, was investigated using the readily diffusible compound 14C-iodo-antipyrine (14C-IAP). Quantitative autoradiography was used to establish absolute values of specific blood flow F for 100 X 100 X 20 microns adjacent tissue volumes of the unperturbed tumour. Mean blood flow to whole tumours was found to decrease with increase in tumour size. This relationship was abolished if blood flow was only measured in sections cut from the periphery of the tumours. Detailed analysis of a sub-group of tumours showed that blood flow to individual tumours was heterogeneous. The range of blood flow was large, indicating that mean blood flow to a whole tumour is a poor reflection of the blood perfusion pattern of that tumour. Necrotic tumour regions were usually very poorly perfused. With the exception of the smallest tumours studied, blood flow was lower in the centre of tumours than in the periphery. Necrosis also tended to develop centrally. However, the peripheral to central gradient of blood flow was apparent even when densely cellular, viable tumour regions and necrotic regions were analysed separately. The decrease in blood flow with tumour size was also apparent in densely cellular, viable tumour regions when analysed separately. Qualitative comparison of tumour histology and regional blood flow showed that there were areas of very low blood flow associated with viable tumour regions. Less common were areas of rather high blood flow associated with necrotic tumour regions. A complicated relationship exists between tumour histology and blood flow. The quantitative autoradiography technique is suitable for investigating the most poorly perfused and the most well perfused viable fractions of animal tumours which may limit the efficacy of different types of therapy.

Animals↗
PubMed1990

The relationship between digital rectal examination and abdominal radiographs in elderly patients.

The relationship between digital rectal examination and the findings of faecal loading on abdominal radiograph was studied in elderly patients admitted to hospital. No significant association was found but there was a relationship between faecal loading of the recto-sigmoid, colonic and caecal areas of the radiograph. Soft faeces in the rectum were commoner in older patients and were associated with faecal loading in the caecal area. The digital rectal examination is useful for identifying anal and rectal lesions and faecal impaction but abdominal radiograph is required to assess faecal loading of the large bowel.

Aged↗
PubMed1990

Caregivers' perception of aggressive behavior in cognitively impaired nursing home residents.

Aggressive behaviors of nursing home residents represent a significant problem for caregivers and families. A guided interview format was used to collect data from 21 nurses and 20 nursing assistants in order to gather information on the characteristics of aggressive behavior and how it is managed in cognitively impaired nursing home residents. Sixty-eight percent of the caregivers stated the residents were physically aggressive, while 95% cited verbal aggression. Aggression occurred most commonly in the mornings while the caregiver was dressing the resident. Inadequate staffing and new staff were both seen as problems by the caregivers. Talking soothingly and assuring the resident were techniques initially used to comfort the residents. Reasoning with the resident was the most common follow-up procedure used by the caregivers.

Aggression↗
PubMed1990

Expression of epidermal growth factor receptor in breast carcinoma.

A series of 90 patients with primary operable breast cancer and with up to 36 months of follow up were investigated for expression of epidermal growth factor receptor (EGFR) in their tumours by immunocytochemical staining with the monoclonal antibody EGFR 1. Tumour samples were snap frozen in liquid nitrogen immediately after resection and subsequently stained using a standard indirect immunocytochemical method. Tumour staining was assessed by two observers and scored on a four point scale (0-3). Thirteen (14%) tumours showed positive immunoreactivity. A strong correlation between distinct EGFR expression and short disease free interval was observed. Significant correlations were also shown with oestrogen and progesterone receptor expression and tumour nuclear size. No significant association was found with tumour size, lymph node stage, and histological grade. The association with disease free interval remained significant in multivariate analysis.

Antibodies, Monoclonal↗
PubMed1990

Delusional misidentification, AIDS and the right hemisphere.

A patient with AIDS developed the Capgras' syndrome as part of an acute confusional state resulting from an opportunistic infection. Neuropsychological testing suggested non-dominant hemisphere dysfunction with impaired facial recognition. Serial CT scanning showed a right parietal lesion which resolved after the psychosis improved. These findings provide further evidence for the hypothesis that selective visuospatial deficits underlie the development of Capgras' syndrome.

AIDS Dementia Complex↗